Interpretive Summary: A metagenomic approach was used to isolate genetic sequence that encodes an enzyme that will break down hemicellulose, a common component of biomass. This enzyme is categorized as a xylanase and will hydrolyze xylan into simple xylose sugars that can then be fermented into value-added products. The xylanase enyzme was over-expressed and biochemically characterized. The enzyme functions from pH 5-7 and has maximum activity at 40 degrees C.

Technical Abstract:
The gene (manf-x10) encoding xylanase from an environmental genomic DNA library was cloned and expressed in Escherichia coli. The encoded enzyme was predicted to be 467 amino acids with a molecular mass of 50.3 kD. The recombinant ManF-X10 was purified by HisTrap affinity column and showed activity over pH range 5.0–7.0 with a maximum activity at pH 7.0 on rye arabinoxylan. The enzyme was thermolabile, and activity was lost above 50°C. The apparent Km and Vmax values obtained for the hydrolysis of rye arabinoxylan at the optimum temperature (40°C) were 2.8 mg/ml and 49.5 µmol/min/mg, respectively.